Examining sympathetic nerve activity with microneurography during hypnosis: untangling the effects of central command.

Using microelectrode recordings of postganglionic sympatheticaction potentials, the authors studied the effects of hypnotic suggestion on sympathetic outflow targeted to skin during static handgrip exercise. All subjects performed sustained handgrip at 33% maximal voluntary contraction (MVC) for 2 minutes during 3 consecutive trials. Two subjects randomly assigned to a hypnosis condition received suggestions that the 2nd trial was more difficult and the last trial was less difficult than the first trial. Two subjects randomly assigned to the control condition received no hypnosis or suggestions about task difficulty. In the nonhypnosis condition, skin sympathetic nerve activity (SNA) increased by 6% from baseline during the 2nd trial and 13% from baseline during the 3rd trial. In the hypnosis condition, skin SNA increased by 25% during the 2nd trial (suggestion of increased difficulty) and returned to baseline during the 3rd condition (suggestion of decreased difficulty). Therefore, the impact of central command on skin SNA is suggested by these results.

S-adenosylmethionine synthetase in bloodstream Trypanosoma brucei.

S-adenosylmethionine synthetase was studied from bloodstream forms of Trypanosoma brucei brucei, the agent of African sleeping sickness. Two isoforms of the enzyme were evident from Eadie Hofstee and Hanes-Woolf plots of varying ATP or methionine concentrations. In the range 10-250 microM the Km for methionine was 20 microM, and this changed to 200 microM for the range 0.5-5.0 mM. In the range 10-250 microM the Km for ATP was 53 microM, and this changed to 1.75 mM for the range 0.5-5.0 mM. The trypanosome enzyme had a molecular weight of 145 kDa determined by agarose gel filtration. Methionine analogs including selenomethionine, L-2-amino-4-methoxy-cis but-3-enoic acid and ethionine acted as competitive inhibitors of methionine and as weak substrates when tested in the absence of methionine with [14C]ATP. The enzyme was not inducible in procyclic trypomastigotes in vitro, and the enzyme half-life was > 6 h. T. b. brucei AdoMet synthetase was inhibited by AdoMet (Ki 240 microM). The relative insensitivity of the trypanosome enzyme to control by product inhibition indicates it is markedly different from mammalian isoforms of the enzyme which are highly sensitive to AdoMet. Since trypanosomes treated with the ornithine decarboxylase antagonist DL-alpha-difluoromethylornithine accumulate AdoMet and dcAdoMet (final concentration approximately 5 mM), this enzyme may be the critical drug target linking inhibition of polyamine synthesis to disruption of AdoMet metabolism.

Multicenter comparison of the nifedipine gastrointestinal therapeutic system and long-acting propranolol in patients with mild to moderate systemic hypertension receiving diuretics. A preliminary experience.

The efficacy and safety of nifedipine in a gastrointestinal therapeutic system (GITS) push-pull osmotic pump formulation was compared with long-acting propranolol in 49 patients with mild to moderate hypertension already receiving diuretics. Using a two-week placebo run-in, double-blind study design, patients were randomly assigned to receive nifedipine GITS (n = 24) in doses of 30 mg, 60 mg, or 90 mg once daily; or long-acting propranolol (n = 25) in doses of 80, 160, or 240 mg once daily. Previous diuretic therapy was continued. Sitting and five-minute standing blood pressure and heart rate measurements were made 24 hours after dosing. At the endpoint of treatment, both nifedipine GITS and sustained-release propranolol reduced blood pressure compared with placebo (p less than 0.001) in the sitting and standing positions. Nifedipine GITS was more effective in lowering standing systolic blood pressure than was propranolol (p less than 0.02). Propranolol caused a greater reduction in resting heart rate than did nifedipine GITS (p less than 0.003). Both drugs were well tolerated. Nifedipine GITS is an effective and safe once-daily drug for use in patients with hypertension who are already receiving diuretics, may be more effective than sustained-release propranolol, and may be better tolerated than conventional nifedipine capsules.

Substrate specificities of 5'-deoxy-5'-methylthioadenosine phosphorylase from Trypanosoma brucei brucei and mammalian cells.

The separation by chromatofocusing of two distinct purine nucleoside cleaving activities from crude extracts of Trypanosoma brucei brucei is described. One catalyzes the reversible phosphorolysis of 5'-deoxy-5'-methylthioadenosine (MeSAdo) and adenosine (Ado) and was designated an MeSAdo/Ado phosphorylase, while the other catalyzes the hydrolysis of adenosine, inosine, and guanosine but not MeSAdo. The substrate specificity of trypanosomal MeSAdo/Ado phosphorylase differed from that of a mammalian MeSAdo phosphorylase (derived from murine Sarcoma 180 cells) in that it was able to phosphorolyze 2'-deoxyadenosine, 3'-deoxyadenosine and 2',3'-dideoxyadenosine. In addition, the trypanosomal phosphorylase was able to utilize the nucleoside analog, 6-methylpurine 2'-deoxyribonucleoside, as an alternative substrate, whereas the mammalian enzyme could not. Because of these differences, cytotoxic analogs of MeSAdo may be designed that are selectively activated by the trypanosomal MeSAdo/Ado phosphorylase.

In vivo effects of alpha-DL-difluoromethylornithine on the metabolism and morphology of Trypanosoma brucei brucei.

The EATRO 110 isolate of Trypanosoma brucei brucei was grown in rats for 60 h and the animals treated with the ornithine decarboxylase inhibitor alpha-DL-difluoromethylornithine 12 h or 36 h prior to sacrifice. Control untreated animals died 72-80 h after infection. Treated parasites were shorter and broader than the predominantly long slender forms found in untreated controls and many had two or more nuclei and kinetoplasts. Trypanosomes were purified from blood and examined for disruption of polyamine metabolism. ODC activity decreased by more than 99% after 12 h treatment and putrescine and spermidine levels also decreased dramatically. Spermine, not normally present in control cells, increased to detectable, low levels (less than 1 nmol mg-1 protein) after 36 h treatment. alpha-DL-Difluoromethylornithine-treated cells were unable to synthesize putrescine from [3H]ornithine but were able to convert [3H]putrescine + methionine to spermidine. 12-h treated parasites responded to polyamine depletion by assimilating radiolabeled polyamines in vitro at 2- to 4-times the rate of untreated cells. The metabolism of S-adenosylmethionine was also altered in treated parasites: decarboxylated S-adenosylmethionine increased more than 1000-fold over untreated cells while S-adenosylmethionine decarboxylase activity, associated with the formation of spermidine and spermine in other eukaryotes, paradoxically declined in treated cells. Synthesis of macromolecules was perturbed in treated parasites: rates of DNA and RNA synthesis declined 50-100%, while protein synthesis increased up to 4-fold in 36-h treated cells. alpha-DL-Difluoromethylornithine treatment progressively limits the parasites' ability to synthesize nucleic acids and blocks cytokinesis while inducing morphological changes resembling long slender leads to short stumpy transformation.

The nifedipine gastrointestinal therapeutic system in the treatment of hypertension.

As the number of antihypertensive agents increases, the choice of optimal therapy becomes more difficult. Certainly, hemodynamic derangements caused by the disease state as well as therapy must be considered. Patient convenience and quality of life are also issues that must be addressed. Preliminary experience suggests that the gastrointestinal therapeutic system (GITS) push-pull osmotic pump formulation of nifedipine is safe and efficacious in the treatment of hypertension. In 1 study, nifedipine GITS was compared with sustained-release propranolol in patients with mild to moderate hypertension already receiving diuretics. Using a 2-week placebo run-in, double-blind study design, patients were randomly assigned to receive nifedipine GITS (n = 31) in doses of 30, 60 or 90 mg once daily, or sustained-release propranolol (n = 32) in doses of 80, 160 or 240 mg once daily. Previous diuretic therapy was continued. Sitting and 5-minute standing blood pressure and heart rate measurements were obtained 24 hours after dosing. At the end point of treatment, both nifedipine GITS and sustained-release propranolol reduced blood pressure compared with placebo (p less than 0.001) in the sitting and standing positions. Nifedipine GITS was more effective than sustained-release propranolol in reducing standing (p less than 0.005) and sitting (p less than 0.001) systolic blood pressure and sitting diastolic blood pressure (p less than 0.02). Sustained-release propranolol caused a greater reduction in standing (p less than 0.001) and sitting (p less than 0.0006) resting heart rate than nifedipine GITS. Both drugs were well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Resistance to DL-alpha-difluoromethylornithine by clinical isolates of Trypanosoma brucei rhodesiense. Role of S-adenosylmethionine.

The ornithine decarboxylase (ODC) inhibitor DL-alpha-difluoromethylornithine (DFMO) has emerged as a new treatment for West African sleeping sickness but is less effective against East African sleeping sickness. We examined uncloned clinical isolates of Trypanosoma brucei rhodesiense, agent of the disease in East Africa, which were refractory to DFMO in laboratory infections, for characteristics that would explain their resistance. None of the isolates were from patients treated with DFMO. Two isolates took up [3H]DFMO at 50-70% lower rates than drug-sensitive strains but ODC activities, Ki values for DFMO, spermidine and spermine uptake rates, polyamine content and inhibition of polyamine metabolism by DFMO were statistically (P < 0.05) similar between sensitive and refractory isolates. One cloned strain, continuously passaged in vivo under DFMO pressure and included for comparison, had > 85% lower ODC activity and up to 14-fold higher putrescine uptake rates than sensitive controls. A statistically important trend was the metabolism of S-adenosylmethionine (AdoMet): activities of AdoMet synthetase and AdoMet decarboxylase were 2- to 5-fold and 3- to 40-fold lower in resistant strains, respectively, while intracellular AdoMet pools (AdoMet + decarboxylated AdoMet) that were > 60-fold elevated in sensitive strains during DFMO treatment, increased only 9-fold in refractory isolates. The extreme elevation of the AdoMet pool in sensitive isolates from 0.7 to 44 nmol/mg protein and an intracellular pool concentration of approximately 5 mM may lead to an imbalance in methylation of proteins or other cell constituents as a consequence of DFMO action. These studies indicate that the metabolism of AdoMet is altered significantly in DFMO refractory isolates and suggest that differences in AdoMet metabolism may be responsible for increased tolerance to DFMO.

The addition of doxazosin to the therapeutic regimen of hypertensive patients inadequately controlled with other antihypertensive medications: a randomized, placebo-controlled study.

This randomized, double-blind, placebo-controlled study evaluated the use of doxazosin as an add-on therapy for inadequately controlled hypertension. Patients with a sitting diastolic blood pressure (BP) of 95 to 115 mm Hg received either doxazosin (n = 38) or placebo (n = 32) in addition to one or two baseline antihypertensive medications. After an upward titration period, patients were maintained on a fixed dosage of doxazosin (1 to 16 mg/day) or matching placebo for 4 weeks. Doxazosin add-on therapy led to improvements, compared with placebo, in sitting systolic BP (adjusted mean change = -20.9 v -8.5 mm Hg, P = .001), sitting diastolic BP (-13.0 v -8.1 mm Hg, P = .026), and standing systolic BP (-22.0 v -11.5 mm Hg, P = .011). Baseline antihypertensive therapy was gradually tapered or discontinued in patients who achieved a target reduction in BP (sitting diastolic BP of < 90 mm Hg in addition to a minimum improvement of 10 mm Hg in sitting diastolic BP over baseline) with add-on therapy (55% [n = 21] with doxazosin, 31% [n = 10] with placebo). Twelve patients in the doxazosin group maintained the target reduction in BP after complete withdrawal of their baseline antihypertensive therapy, compared with none in the placebo group. A small but statistically significant positive effect on the lipid profile was seen in the doxazosin group during add-on therapy. Doxazosin treatment was well tolerated, with an adverse event profile similar to that of placebo. These findings demonstrate that doxazosin add-on therapy is an effective, well-tolerated treatment strategy for patients with inadequately controlled hypertension.

Socioeconomic status and chronic stress. Does stress account for SES effects on health?

Socioeconomic status (SES) is an important predictor of a range of health and illness outcomes. Research seeking to identify the extent to which this often-reported effect is due to protective benefits of higher SES or to toxic elements of lower social status has not yielded consistent or conclusive findings. A relatively novel hypothesis is that these effects are due to chronic stress that is associated with SES; lower SES is reliably associated with a number of important social and environmental conditions that contribute to chronic stress burden, including crowding, crime, noise pollution, discrimination, and other hazards or stressors. In other words, chronic stress may capture much of the variance in health and social outcomes associated with harmful aspects of lower social status. Low SES is generally associated with distress, prevalence of mental health problems, and with health-impairing behaviors that are also related to stress. Research targeting this hypothesis is needed to determine the extent to which stress is a pathway linking SES and health.

Toward more accurate use of the Beck Depression Inventory with chronic back pain patients.

OBJECTIVE: To improve the accuracy of the Beck Depression Inventory (BDI) in assessing depression in chronic back pain (CBP) patients, the pattern of depression symptomatology was evaluated. DESIGN: Analyses of BDI data obtained from nondepressed and depressed CBP patients were conducted to identify the major factors that differentiated among the patient groups. SETTING: CBP patients were recruited from a tertiary rehabilitation center. PATIENTS: One hundred one nondepressed and 99 depressed CBP patients from the tertiary treatment center. OUTCOME MEASURES AND RESULTS: Analyses of the BDI data revealed a general factor of depression severity that excluded items reflecting weight loss, sleep disturbance, and work inhibition. In addition, these analyses yielded a second factor reflecting somatic concerns and disability. Weight loss, sleep disturbance, and work inhibition failed to differentiate the depressed from the nondepressed CBP subjects, suggesting that these symptoms have poor diagnostic potential for CBP patients. CONCLUSIONS: This study demonstrated that the BDI can be used to generate important information about the severity of interference posed by pain on the functioning of an individual, while allowing for an independent evaluation of subjective indices of depression and somatic disturbances that need to be attended to by clinicians.

Pregnancy outcome. Influence of antiphospholipid antibody titer, prior pregnancy losses and treatment.

OBJECTIVE: To evaluate the effectiveness of combination therapy in preventing fetal loss in women with circulating antiphospholipid antibodies and a previous history of adverse pregnancy outcomes. STUDY DESIGN: We identified 18 pregnant women with antiphospholipid antibodies who had a total of 59 prior pregnancies. Of these pregnancies, spontaneous first-trimester abortions occurred in 36 (61.0%); fetal demise after the first trimester occurred in 9 (15.2%); voluntary terminations were elected in seven (11.9%) pregnancies; and there were seven (11.9%) surviving infants. During their next pregnancies, these patients were treated with prednisone and/or low-dose aspirin. RESULTS: Fourteen patients delivered successfully between 33 and 39 weeks' gestation, resulting in a live birth rate of 77.8% and a pregnancy loss rate of 22.2%. We also observed an association between the number of prior fetal losses, the anticardiolipin antibody titer and the fetal survival rate following therapy. Two or more prior fetal losses and high autoantibody titer resulted in a fetal survival rate of 50-75% with varying therapeutic regimens and dosages. However, an improved fetal survival rate of 75-100% was observed with less than two prior fetal losses and low-mid anticardiolipin antibody titer with the same therapy. CONCLUSION: Therefore, the results of this study suggest that although pharmacologic prophylaxis improves the outcome of pregnancies complicated by circulating antiphospholipid antibodies, such an outcome is influenced by the number of prior fetal losses and the anticardiolipin antibody titer.

Major psychological disorders in acute and chronic TMD: an initial examination.

This study assessed psychological disorders in 50 patients with chronic temporomandibular disorders and 51 patients with acute TMD. The results revealed a significant psychological comorbidity in both groups of patients. Both groups had high rates of psychopathology that exceeded the base rates of the general population. Such findings are in keeping with an integrated biopsychosocial model of TMD, and have significant implications for treatment of these patients.

Predicting chronicity in acute temporomandibular joint disorders using the research diagnostic criteria.

The authors describe a prospective study designed to examine the clinical utility of the Research Diagnostic Criteria for Temporomandibular Disorders, or RDC/TMD, in evaluating physical and psychological differences between patients with acute TMD that does not become chronic and patients with chronic TMD. A total of 153 patients with acute TMD participated in the study; the researchers deemed the condition of 87 of these patients to be chronic after a six-month follow-up period, and that of 66 patients to be nonchronic. Using a multiple logistic regression model, the authors found that a number of physical and psychological variables differed significantly between the two groups. These results highlight the importance of the physical-psychosocial interface that affects the development of chronic TMD.

Identification of a new physically induced urticaria: cold-induced cholinergic urticaria.

Four patients with symptoms suggestive of either cold urticaria or a combination of cold and cholinergic urticaria were studied. However, all patients were negative to an ice-cube test or cold-immersion test and had no urticaria after exercise in a warm environment. When each patient was seated in a cold room (4 degree C) for 5 to 15 min, generalized urticaria appeared, consisting of puncture wheals and surrounding erythema as seen in cholinergic urticaria. Two patients had weakly positive methacholine skin tests and the other two had completely negative tests. When serial venous blood samples were obtained to test for mediator release, three of four patients had evidence of histamine release and the time course was similar to that previously reported for patients with cholinergic urticaria. These four cases represent a new syndrome with features suggestive of cold and/or cholinergic urticaria, but the results of all the tests usually utilized to diagnose these conditions were negative. We have called this disorder cold-induced cholinergic urticaria to indicate that it is cold dependent and visually indistinguishable from cholinergic urticaria.

A controlled trial of self-nonstress test versus assisted nonstress test in the evaluation of fetal well-being.

OBJECTIVE: New portable devices have become available for home monitoring of fetal heart rates; these devices have the potential to immediately transmit these tracings to a medical facility. The null hypothesis of this study is the inability of mothers to perform their own nonstress tests (self-nonstress tests) and that such tests are not comparable to those performed by professional medical personnel (assisted nonstress tests). STUDY DESIGN: The feasibility of maternal self-testing was established in 50 high-risk patients followed by a controlled clinical trial conducted in 60 patients. The latter study represents the first controlled trial in which patients performed self-nonstress tests at their homes and transmitted the tracings via telecommunication to our perinatal unit. In all cases these patients came to our hospital within 60 minutes after the self-nonstress tests to have a perinatal nurse perform a second nonstress test. The pairs of self and assisted fetal heart rate tracings were independently reviewed by two investigators. RESULTS: The self and assisted tracing pairs were judged satisfactory for interpretation in 100% and 90%, respectively; self and assisted were interpreted by each examiner to be nonreactive in 20% and 14%, respectively. However, both examiners were unable to distinguish between tracings generated by assisted nonstress and self-nonstress tests. Furthermore, cost analysis revealed an estimated twofold savings with self-nonstress testing compared with the assisted nonstress test. CONCLUSION: Self-nonstress testing is a reliable and accurate method of antepartum fetal heart rate testing. This method of fetal assessment not only introduces a new approach to fetal surveillance with added convenience to patients, but may also significantly reduce medical cost without compromising the results of fetal testing.

Differential sensitivity of Trypanosoma brucei rhodesiense isolates to in vitro lysis by arsenicals.

Clinical isolates of Trypanosoma brucei rhodesiense, which were resistant to arsenical drugs in murine infections, were examined for resistance in vitro. A rapid lysis assay was developed which was able to predict in vivo sensitivity to melarsoprol (Mel B, Arsobal) and melarsen oxide. The assay was based on the finding that long slender bloodforms of drug-sensitive isolates would lyse in the presence of arsenicals upon incubation in heat-inactivated fetal bovine serum. On the basis of plots of decrease in the absorbance of trypanosome suspensions vs time of incubation with drug, L50 values, reflecting the drug concentration necessary for lysis of 50% of the cells within 30 min. were calculated for five strains. These values ranged from less than 30 microM for arsenical-sensitive strains to greater than 75 microM in proven arsenic refractory isolates. Calcium was essential for lysis, and the presence of the Ca2+ chelator EGTA (10 mM) in serum delayed lysis of sensitive strains. Ca2+ channel antagonists (Verapamil, Diltiazem), however, did not enhance lysis of refractory isolates when used at 20 to 30 microM. Intracellular concentrations of reduced trypanothione, the apparent target of arsenicals, were similar for all isolates, approximately 1.02 +/- 0.28 nmol/10(8) cells, as detected by monobromobimane derivitization and HPLC analysis. Uptake of melarsen oxide was found to be reduced in arsenical refractory strains. Uptake was judged by reduction of free reduced trypanothione as a result of formation of the trypanothione-arsenic complex Mel T. Little change was found in arsenical-resistant strains, but sensitive strains had 50 to 70% reductions in trypanothione levels after incubation with a low (1 microM) level of melarsen oxide.

Synthesis and content of polyamines in bloodstream Trypanosma brucei.

The sensitive dansyl procedure was used to detect putrescine and spermidine, but not spermine and cadaverine, in pleomorphic Trypanosoma brucei. The polyamines were synthesized in vitro from [3H]ornithine, [14C]arginine and [14C]methionine. Proline, agmatine, and citrulline, but not glutamine, glutamic or pyroglutamic acids, stimulated spermidine formation from [4C]methionine. Putrescine and sperimidine synthesis occurred rapidly from ornithine: putrescine synthesis peaked in 0.5 h, spermidine in 1 h. Trypanosoma brucei assimilated exogenous 14C-labeled putrescine, spermidine, and spermine; spermidine and spermine were taken up 5 times as rapidly as putrescine. Polyamine syntheses may therefore be a practical target for novel trypanocies.

Surface markers on lymphocytes of patients with infectious diseases.

PERIPHERAL BLOOD LYMPHOCYTES FROM NORMAL SUBJECTS AND PATIENTS WITH VIRAL AND BACTERIAL INFECTIOUS DISEASES WERE EXAMINED FOR THE PRESENCE OF THREE SURFACE MARKERS: (i) surface immunoglobulins, (ii) receptor for C3 complement component (EAC test), and (iii) spontaneous binding of sheep red blood cells (E rosette formation). The first two markers are used to detect bone marrow-derived lymphocytes (B cells); the E rosette formation is dependent on thymus-derived lymphocytes (T cells). We demonstrated these assumptions, as defined by others, by the fractionation of lymphocytes on bead columns coated with immunoglobulin plus anti-immunoglobulin. The peripheral blood lymphocytes of normal individuals consisted of 52% T cells, 23% B cells with EAC receptor, and 21% B cells with membrane immunoglobulin. There was no significant difference in these values from those obtained in viral or bacterial diseases. Only a few cases of infectious mononucleosis had an increase in T cells. These results give us a partial picture of the T- and B-cell frequency in normal subjects and in patients with infectious diseases.

Trypanosoma brucei brucei: regulation of ornithine decarboxylase in procyclic forms and trypomastigotes.

Ornithine decarboxylase (ODC) activity was measured in procyclic forms of Trypanosoma brucei brucei grown in semidefined medium. ODC activity rapidly increased in late log-phase cells which were resuspended in fresh medium. A biphasic induction curve similar to that observed in mammalian cells was observed over an 18-hr period. ODC activity increased 4.5- to 25-fold over control levels measured at zero time. Actinomycin D and cycloheximide inhibited induction by greater than 90%. Polyamines at a level not inhibitory to growth (10 microM) inhibited ODC induction, but only by 30-50%, late in the induction period. Putrescine inhibited the first peak of induction and suppressed activity at 14 hr by 75%. Polyamine analogs such as bis(ethyl)spermidine were not effective suppressors of ODC activity. The half-life of ODC in procyclic forms grown in the presence of cycloheximide was greater than 6 hr, while that of bloodstream trypomastigotes in mice treated with cycloheximide was 5 hr. A single dose of the ODC inhibitor DL-alpha-difluoromethylornithine given to infected rats or mice suppressed trypanosome ODC activity greater than 90% for more than 7 hr. These studies indicate that although trypanosome ODC increases rapidly under log growth conditions, it is less susceptible to fluctuation and external control than the enzyme from mammalian sources. The latter may be a factor in the clinical efficacy of ODC inhibitors.